The present invention relates to fuse ejectors and ejection systems and methods for assembling fuse ejection systems.
The installation or removal of elongated fuses from a fuse clip chamber, such as a fuse block, switch block or other type of fuse holder, involves overcoming bias resistance in order to remove the fuse from electrical contact sets, which are also called fuse clips. Tight clearance around the fuse clip chamber which holds at least one end of the fuse may well prevent an electrician from establishing a good grasp of the fuse barrel by mere finger contact.
Over the years, devices have been created to aid an electrician with fuse removal. Tools of the type which aid fuse removal include clip-on type pliers that are used to grasp the fuse barrel between the contact sets or pliers having C-shaped jaws which grasp the fuse barrel.
Other types of fuse puller tools are constructed as an integral part of the fuse clip chamber enclosure. Such types of fuse pullers include loop-type pullers which circle one end of the fuse with a generally elongated O-shaped ring which rides in a track built within the fuse clip chamber or the contact sets. Another kind of loop-type fuse puller is a strap which passes under the fuse barrel, one end of which is connected to the fuse clip chamber and the other end of which acts as a pull lanyard. Another type of fuse puller integral with a fuse clip chamber is an spring-loaded ejector assembly which holds the fuse and ejects as a cartridge with the fuse. Another type of fuse puller is an ejector lever which is pivotally-attached to the fuse clip chamber or the fuse clip and includes a rigid loop constructed on the lever in which rides the fuse barrel. Rotation of a handle on the lever creates a torque moment, which disengages the fuse from fuse clips. Such a lever-type fuse puller is shown in U.S. Pat. No. 3,518,599.
The prior known fuse pullers have disadvantages. Clip-on and plier-type fuse pullers are not an integral part of the fuse assembly and may be misplaced, or the electrician may not have the tool handy when needed to replace or install a fuse. Also, while clip-on and plier-type fuse pullers may be satisfactory for relatively low amperage fuses, they do not provide the additional leverage to disengage industrial-size fuses. Loop-type and strap-type fuse pullers also do not provide additional leverage for removing fuses.
The application of ejector-type fuse cartridges is limited as fuse size and weight increases, due to the amount of force which must be generated by the spring-loaded ejector. Spring-loaded ejector assemblies and cartridges are relatively complex and increase manufacturing costs.
While lever-type fuse ejectors, such as shown in U.S. Pat. No. 3,518,599, provide additional leverage for ejection of fuses, the lever design shown in that patent, due to the nature of its construction, does not maximize fuse insertion and removal efficiency and is too complex for modern fuse clip chamber manufacturing techniques. The fuse ejector lever shown in U.S. Pat. No. 3,518,599 is constructed of multi-piece stamped metal components and has a stirrup which completely encircles the fuse. Where such an assembly lever is used in a narrowly confined location, the electrician has difficulty inserting or removing the fuse from the stirrup, because it is analogous to threading a needle. In addition, the lever assembly shown in the '599 patent does not facilitate mass production of ganged assemblies of fuse clip chambers which must be manufactured at low cost. Contemporary manufacturing techniques stress reduction of subassembly component quantities and maximization of the use of components which are capable of being manufactured of plastic.
It is an object of the present invention to create a fuse ejector which provides mechanical leverage for ejecting fuses from their biased fuse clip assemblies.
It is another object of the present invention to create a fuse ejector which allows easy insertion and removal of a fuse from the ejector, even in narrowly confined locations.
It is also an object of the present invention to create a fuse ejection system which allows efficient production assembly of fuse ejectors within fuse clip chambers, including ganged fuse clip chambers, which have a plurality of fuse clip chambers and ejectors in tandem, side-by-side relation.